5.5 people per square metre (550 people in 100 square metres) - HIGH RISK

6 people per square metre (600 people in 100 square metres) - HIGH RISK

From the links below you can view a 10m grid, against a tennis court backdrop, to assist in visualising crowd densities and crowd sizes. I'm going to produce a whole range of crowds against backdrops to act as both a training aid and to provide reference visuals for assessing both density and crowd numbers.